If you have a specifically designed Engine Out Procedure for the TO calculation. That means you are not able to meet the gradient requirement on straight out departure and, potentially, the required climb gradient (which can be higher than the 2.1%) on the designed Missed Approach.
One could argue, that you then fly the EO SID for a Missed Approach, which could be your out of jail card.
Other problem could be that the departure Runway hasn't got the required Approach Aid for the Landing and the Landing Runway has a higher Missed Approach Climb Gradient requirement.